Compass variometer



'.Feb. l2, 1929.

L. A. BAUER ET AL COMPAS S VAR IOMETER Filed June 28, 1926 5Sheets-Sheet lll ndi?? lullin...

\ Feb. l2, 1929. 1,701,603

L. A. BAUER ET AL COMPASS VARIOMETEP.

Filed linge 268:5 1926 5 Sheets-Sheet 2 Feb. 12, 1929. 1,701,603

l.. A. BAUER ET AL,

COMPAS S VARIOMETEE Filed June 28, 192e 5 sheets-sheet 3 Feb. 12, 1929.1,701,603

` L. A. BAUER ET AL.

COMPASS VARIOMETER Filed June 28, 1926 5 Sheets-Sheet 4 12.14.. Bauer717.2): P52125 JH.

@Mmm-7%@ Feb.` 12, 1929.

` L. A. BAUER ET AL COMPAS S VARIOMETEH Filed June 28. 1926v 5Sheets-Sheet 5 Patented Feb. 12, 1929.

vente u 1,701,6e3 ArtNr .Fricsp .to frs e. BAUER, or wiisnrneiron,vnisrnrer er eoLUiirnIAQAnn winsten: J. 'Premieres p te, ener/*Ycnnsnfmiinrmnn nssrenons TOCARNEGIE eoMPAss viinIoMnTEn.

nppncatiqn md nine 2s,

rlhis ometer invention rel-rites to :i compass-variwhich is usedprimarily ifor the de tectien and measurement of slight changes in theearth-s magnetism. It een be veniployed ior rapid surveys of highprecision end in investigations of magnetically dis turbed regions suches magnetic iields in buildings7 magnetic fields Abont iron ships, andregions of local disturlnince in the ezirths magnetic field. It may alsobe empioyed desired for vobserving changes in nag-nette declination.

'lfhe Jundsmental principle of the coinpziss-Vziriometer may bedescribed briefly es follows:

Two magnets ofi equal or unequal magnetic moment are suspendedindependentlgy vone above lthe other s i'id are so inouji :ed that thedistance between them may be Varied in order to maintain s xedhorizontel deflection angle for any particular intensity of iield, eventhough it may not be known.

"lhere' ire herein disclosed three forms oit compess-veriometer, all ofwhich embody the iiundementel principle etuted und which in manyrespects :ire quite similar, while di?" ring in c *ein tentures and yintheir por -cular physical construction. ,Further ietnils oi theinvention will be .apparent from the. following description and thewhole wiil be couered by the appended claims.

4in the drawings:

Fig-ure l is :i section teken on the line lM-l, of Figure fiooiriup'y inthe direction of the arrows.

Figure 2 is :t vertical section througlli one forni oi the inventionwith parts in. ele- U o is e View showingy a detail of construction. Yf' liivure is u'top plain View with ports ser ion oi5 another embodimentof ,the ntion.

gure 5 is e side elevation of the structure snown in Figure t.

ojnre 6 is s` section on the line 6--6 of ire e, looking; in thedirection ot' the Figure 7 is e. side elevation of e. third ein- 1926.serial No. 119,095.

dii

'ent ferm ot cell :ind showing netic disk. y

Referring to the` form of invention jillustrzitedin Figures 1,2 end 3,ythis embodies :i supporting ring l which is carried by e plurality oicfoot screws@ which can be ndrmv oit suspension of the meg- G0 jure is usimilar sectonthrough e. 1

justed in the usuel manner 'for leiffeling the device. Mounted forrotationfwithinfthe support lr is a base' which may be clamped in anydesired position by means off'the clamping* screw 4. Thenpper surisce of1 il' port l is provided witha. scale 5; and the bese tcli een bevbrought to register with. nny red gradetion oit the scale 5. Theiro'l'tom ot the bese member 3 is preferably closedb'i/ al "ground glass6 held in position by 'a ring Tastened to the bese by screws 8. iifhisprotects tl'ie bottom ot thecese sind sise furnishes the desiredillumination.

A ring @rests upon the top of the bese i3 inside of the easing endprovided with e plurzlity of spider arms l() which Gerry irbeuringirsleeve l1 at approximately the nl axis of the device. The rin-g 9 isyned to the lower end ot s horizontel casing; which i-estsupon the buseApproximately midway between top and bottom oi the fesingg u secondring/13 supporeilon :i shoulder of the casing); l2 und havingr spiderfirms le supporting a. beeris provided with an indenmerlrl ing sleeve l5in vertical valignment with the Y ieri magnet l? is pr rsbly formed ote.

fhnl steel which may be nim. in dromer" :ind 0.3 inni. in thickness. und

copper-plated to protect egrsnist deteriora.-k

tion. in this embodiment et the invention euch magnet l? is supportedwitliinsi copper dziniping box ,i8 havinge' coverli?) provided witlr ecentral opening. `Esch magnet is supported'by e cone shaped menil'iei-ZOhi'vv ing its small end upward and having a jewel 21 set in said upperend. To the top ot this cone shaped member is att-ached a quartz pointer22 which will indicate the magnetic axis ot' the disk or any desiredangle thereto. The magnet 17 and the cone shaped. member 2O aresupported by means ot a pin 23 carried by the base ot the box 1S andhaving a needle pointuponwhich rests the jewel 21. The magnet istherefore supported for tree oscillation on a substantially irictionlessbearing.

A rod 2%1- is attached to the bottom oi the upper box S and slidablymounted in the biaring sleeve 15. A similar rod 25 is attached to theunderside ot the lower box 1S and is similarly mounted for slidingmovement in the bearing sleeve 11. A lever has an upper arm 28 and alower arm 27 which are pivoted together at i8 and a second similartoggle lever has an upper arm 29 and a lower arm 30 pivoted together at31. The upper arms Q6 and 29 of the two toggle levers are both pivotedto the rod 24 at 32. rlhe lower arms 29 and 30 are similarly pivoted at33 to the rod 25. t is obvious that by movement oi the toggle levers therelative position of the magnets may be changed as desired.

rlhe movement of these levers is obtained as follows: The rod 34 ispivoted to the levers 29 and 30 by the pivot 31 and this is slidablymounted and connected to a member 34 which is screw threaded in abushing 35 mounted in a boss 86 of the casing 12. rlhis member may beturned by means cfa linger wheel 37 and will of course move the rod 34in or out according to the direction of rotation. This movement willopen or close the two pair ot toggle levers and move the magnets to orfrom each other. The amount ot n'iovement is measured by micrometermechanism comprising a wheel 3T connected to the member Si and having ascale 38 which coacts with a scale 39 carried by a split sleeve 4l) onsaid bushing 35. The use of this micrometer mechanism is obvious to anyone skilled in the art. Whenever it is desired to hold the magnets inany adjusted position this may be done by means of a screw l2 whichclamps together the separatejaws Ll1 oi the member 40 and preventsrotation of the adjusting member 34.

Approximately halin way between the pointers 22 of the two magnets is aglass plate i3 resting on the spider arms 1d and having a centralopening. A mirror let which is annular in form surrounds such centralopening and outside the mirror a scale i5 is photographed upon the glassplate. A milled ring 46 surrounds the outside of the casing and has aconnect-ion to said glass plate extending through an are shaped slot oi'approximately 90", whereby rotation of said ring will rotate one or morequartz indices 48 mounted on the movable index ring 13 just described.

Resting on the bottom ot each casing 18 is a plate 4.9 having a centralopening 50 through which passes the supporting pin rlhis plate also hastwo projections 51 extending downwardly through openings in the bottomci? the case 18. Between ears oarried by the inside or" the casing 1 ispivoted the lever 53, one end ot which has a ilexible extension 5dterminating in a iorlr 55 1') the arms of which underlie the pins orprojections 51. rlhe screw 57 having a head `for manual adjustment, isscrew threaded in a boss 5S on the outside of the casing and yextendsthrough the casing so that the inner end ot the same bears against thelower eno 56 of the lever 53.

1f the screw 5l is turned so that it moves inwardly the lever 53 will berocked about its pivot point and the `fork 55 will engage theprojections 51 and the raise the plate 1.9. rlhe upper surface ot thiswill come in Contact withl-"the coneshaped member 20 rand litt the coneand magnet so that the jewel 21 will be lifted clear oii its suspensionpin 23. At the same time the cone will be brought into contact with thesides ot' the opening in the cover 19 ot the box 18 and can be clampediirmly in position. This is to prevent any accidental injury to themagnet and the quartz pointers when the instrument is being transportedor is not in use.

The inner side of the casing has attached thereto an arc shaped shelf 59upon which is supported a similarly shaped thermometer GOQ The indexpointer 22 of one magnet is attached theretoso that it will lie in theniagnetic axis ot the magnet. The pointer attached to the lower disk isset oil at an angle ironi the magnetic axis of this maj t and this anglemay be varied, but is usually chosen as 60. lVhatwer the angle betweenthe two jiointers may be7 it is obvious that there mightbe two positionsseparated by the complement oiI the chosen angle. ln order to preventdisplacement oit the pointer Q2 there are attached to the spider arms 14vertical. quartz rods (51 which extend into position to engage thepointers 22 and prevent their swinging beyond a limited range.

Vhen it is desired to use the instrument, the head ot the micrometerscrew is turned until the two pointers coincide. This is the Zerosett-ing and may be read on the micrometer head. Looking through thereading lens the observer sees the pointer of the lower magnet directly'and the reflection of the pointer ot the upper magnet in the mirror t.This eliminates parallax, and makes it relatively easy to set the twopointers in coincidence. lVhen the zero setting has been made for anyparticular location oi the instriiunei'i-t, any change in the ield isdisclosed by an opening or scrssorine; of the two pointers, and theangiilalr' vamount ot wh"` h can be read on the scale lio.Theorientation of the instrument may be controlled in connection with asuitable sightingl device by means of the scale 5 on the base 'member l.The instrument may also be used through orientation on a lined magnetfor the puru pose of observingq changes in magnetic dec'- lination bymeans oi the quartz index i8 inoimtcdv on the movable index ring'.

Figures el, 5 and 6 disclose a second emlmdiment of the invention whichoperates on the salue principle as docs the first. in this constructiona ring G2 is provided with ears G3 by means of which it may be supportedinside a casing- (not shown) for slight oscillatory movement. Alt rightangles to the car 63 the ring las cut-outs Gli in which eers 65 onsleeves 66integral with a ring G7. These ears are held in position by acover plate 68 at the top and a similar cover plate 69 at the side. Thisform of suspension has been found very useful for observations on sea.

A spider havingl four arms 'Z0 anda cential web 7l (Fig. 6) issupportedby the ring 67. By means of appropriate clips 72 there issupported on each pair or". arms arc-shaped plane mirror 7 One sleeve 66is carried by a? guide rod 741- which is supported in suitable manner inthe casing. The other sleeveGG has a rod 75 passing); therethrough, thisrod being provided vwith a right hand screv.' thread 76 above the sleeve66 and a left hand screw threes. 77 below said sleeve. A sleeve 78 isinternally threaded and carried" by the right hand threaded portion ofthe rod 75. This sleeve has a supporting bar 79 rigid or integraltherewith which entends to the opposit-e sido and is provided with afoi-lied end 80 which slidably engages the guide rod 74. A lower sleeve8l is internally threaded and mounted on the left hand threaded portionoi1 the rod 75 and this is provided with a supporting` posite side andhas a forked end 83 engaginev the guide rod 74. Since this mountingprevents any rotative movement ofthe bars 79; and 82 or the sleevesconnected therewith, it is obvious that if the rod 75 is rotated thebars mend 82 will be moved toward or from cach Vother according to thedirection of rotation of the rod 75. rlhis mechanism is employed formoving the magnets toward or 'from each vother as desired. The rod 75 isrotated by micrometer screw nechanism similar to that herein describedin conncc` bar 82 which extends to the opy Near the middle of the bar 79is supported ina 8ewhich is substantially the saine ae that described inconnection with the first form oi' the invention and has a al coneshaped member 85 carrying` a jewel in its end which is sujiportel u onthe pin lt provided with a (piartzpointer or indicator 8?. ylhedisplacement of the inaenet is prevented rby an arch-shaped metal strip88 which is fast at its ends to the ber 79 and extends over the upperportion of the cone shaped member and the indicator without contactingtherewith. y

The lower magnet 8i is .supported .on the bacSQ in exactly similarmanner and needn no further description.

Two members 89 and 90 have their parallel middle portions `supportedont-he bar 79 at opposite sides oit the center thereof and each end oithese members have divertiing poi m i ihe end portions of these menibeissupport scales 91 having gradations 92 on the inner Vertical facethereof. lnsi `e oii the scales and supported` by the members 89 and 90are two mirrors 93 having outer reflecting surfaces arranged at an angleoil.E 1h30 and iacingthc gradations of the scales 9i. The arrangement ofthe quartz indicators carried by the magnets, the mirrors 73 the scales9i, and the mirrors 93, is such that when the instrument is supported inposi ion an observer looking* directly downward will see the re'liectionof the upper pointer 87 in the mirror 73, will sce the lower pointerdirectly, and will read the gjradations ot the scale 91 on the mirror 73since these have been reflected by the angular mirror 93 downward uponthe mirror 73. rlhis arrangement will entirely eliminate parallax, sincethe lines oit sight are allot equal length.

For preventing the magnets 'from talip; up an erroneous position, thereare provioed as in Ythe iirst torni, queria bumpers. 'fho upperbun'lpors 95 are iour in number and carried by the ineubcrs Si? and 90.lhe lower bumpers 9G are ali-1o tour in number and are constituted bytheupturned ends of two nicinl. ei's nioui'ited upon the lower bar 82. Themechanism thus described 'is employed in the saine `manner as therstform oi the device and needs no further eX- planation. lt is intended tobe supported in a casing` closed by a reading lens and instead of theelectromagnetic damping; eniployed in. the i'irst form, .liquid dampingis employedf The eijuire casing containing the instrument is filled withya suiti .ile liquid. This liquid must have certain properties such astransparen permanency, ineriness and mobility at ordinary temperatures.should yalso be asheev as possible. Gasoline has usually been employedbut experi-- ments made kwith acetylene tetr bromide appear to show thatthis liquid be' very ity satisfactory. rhe damping); liquid will alsoact to a certain extent as a lubri ant tor the various pivoted bearings,particularly those of the magnets.

A third form or the invention is disclosed in Figures 7 to 11 inclusive.In this confstructi-on a base 07' is supported on feet 08 which may beadjustable it desired. tor leveling; purposes. r1`wo shafts or rods 90and extend upwardly trom the base and port a top plate 101. The shalt100 may oc fixed in both top and bottoni plates but the shailt 9S)nounted for rotation but. pre- `vented troni endwise moreinent in thetop and bottom plate-.1. A carriage 102 has guide sleeve 105 throughwhich passes th rod 100 and has a split sleeve 101 which i. internallythreaded to engage Vleft threads 105 on the rod'QQ. A similar carriage10G has a sleeve 10T throuejh which the rod 100 passes and a splitsleeve 108 which is internally threaded to enorme right hand threads onthe red 99. The-sc 102 and 10G support cells 109 and means of screws 111which screw into the carriage base and have eccentric heads oyerlyingflanges on the cells. Each cell has a reference mark indicate(L at l5which is to be placed in registry with a Correspendingl mark on the.carriage in order that the cell may be properly positioned.

The shaft 99 may be turned by means of a. linger wheel 112 at the upperend thereof and the degree oit turning movement may be registered bymeans oi.' the micrometer mechanism 113 ot any desired type. rThisconstruction is the same or similar to that employed for t rninel theshaft Grin the modification shown in Figures L1, and lt is obvious hatby turning the linger wheel 112 the shait 99 will be rotated and thesleeves 101 and 108 will be caused to travel either toward or from eachother in equal degree, due the right and lc'l't hand threads on theshaft 00. T

liano V'ne distance between. the two cells which contain thc niagnetscan therefore be adjusted as desired and with grea accuracy.

Attached to and depending; from thAx to plate 101. are four similarbracliets and brackets 114 carry smooth `'uide ro ls 11o.

he other two brackets 116 support threaded p uidc rodsl 11T. rhe beveledgear 118 is rtast on the shalt 99 and meshes with oeveled gears and 120which are on the two shafts 117.

r1`wo lenses 121 are carried by frames 122 each of which has a smoothsleeve 123 through which passes the correspondin@` rod and also aninternally threaded split sleeve 124: which meshes with the screwthreads on the shafts 11T. lt will be oh vious from this constructionthat as the linger piece 112 is turned to rotate the shalt 99 and adjustthe magnet carrying` cells i rllher transverse bar 125 (see Figure Q issupported against movement on tie shafts 09 and 100 and has fixedthereto two right angular speculum prisms 12 and 12T or sii .ilarre'lectors; n

ln this embodinie it olf 'the invention liquid damping is employed as inthe second torni above described, but instead of i lacingrl the entireaaparatus in a casing lilled with liquid each magnet placed in a similarcell which is closed and filled with the dani-pinev liquid. rlwoconstructions or cells are illustrated which are similar in mostrespects but diiierent in minor details. One form 12T is illustrated inFigure 10 and the other form 12S is shown in Figure 11. The points inwhich the two cells are identical will tiret be described.

Each cell has a base 129 supporting` the short glass or othertransparent cylinder 130 upon which rests a top 131. rlhe base hascentral circular opening' 132 which closed by a glass or othertransparent meniber 133 held in position by a ring); 125 threaded in thesaid base. The top has a similar central opening 135 rclosed by a glassor other transparent member 136 held in position y a ring 137 threadedinto said top. rlhe top and base members are held together by aalurality of rods r similar fastening; devices.

ln order to provide for expansion of the dan'iping liquid during`temperature changes, the top member is provided with a plurality oiPAcavities 130 which are closed at the top but counnunicatc with theinterior of the cell by small openings. rlhis permits the liquid to passtrom the central portion oi the cell to these cavities as it expands,but the openings are so small that no splashingr` movement can be set upwithin the cell.

1n the foi-1n shown in Figure 10 a b idred piece 140 an arched member141 supported by the base are each provided with jewelled bearings withwhich engage two ends oit spindle 142 which supports the magnet 1&3.This gives a two point support 'for the magnet. ln this modificationalso is illustrated the use ot a wire gauze 14e/l inside of the glu. scylinder to protect against possible velectrical disturbances occasionedby the action of the wind on the exposed glass sur-tacos. Althoughillustrated only in connection with the cell in Figure 10. it is obviousthat this n'iay be used with the other form of cell. Y

lho ma et support in Figure l1 is of the single bea ing type such asthatshown in the lirsty andsecond forms of the invent" above described. Thesupports a pi* member ifi-,5, the pointed end ot which ei with a ewelbeam'H f in the upper end of a cone la? which supports the magnet 14H8.An arch member 149 carried by the base prey vents displacement this conebut is normally out outA Contact 'f e ewith.

is illustrated n l!" ure 9 there are provided quartz fiber ind rods l5@which are mounted just belowthe magnetized dish to give a fixedreference line. Since as above described, there are two possibleequilibrium positions lor the same vertical distance betweenthemagnjets, there are provided :tour short quarti-g `fihi-ir bumpersllk which are mounted symmetrically on perpendicular fdiameters in thedisk inagmets.V These are just loira` e; ioughlto touch Pthequart-zlibre index rods and therefore restrict the departure of magnet systemsfrom equilibrium to an anale of o on either side in such position.

Each magnet is provided with an index scale the-reen, this being placedon the under side of the upper magnet and on the top side ol" the lowermagnet. An observer at the point A of Figure 9 looking through thelens'lQl will by means of the mirror 126 read the scales of both theupper and lower magnets and can therefore determine the angle existinglbetween the same. rllhe two lenses 121 are provided to permit ofsimultaneous observation by two observers or in order that one lens maybe used when the instrument is located in a more appropriate positionthan it is l'or use of the other lens. The method of employment of thisform oi the device is substantially the same as that of the previousforms and need not be described in detail. lt may be noted only that foruse on board ship it has been found quite desirable to mount this formin an inertia gimbal system in order to differentiate the regularoscillations of the magnet from those caused by passing' over a smallarea of local disturbances. V

lt is .obvious that the invention may be embodied in other forms withoutin any way departing` from the fundamental principle underlying* thesame and also that the precise construction illust ed maybe departedtherefrom in details without in any way depeutiim` from the spirit ofthe invention. It is therefore understood that the invena El) lancestow-il 0r from will ether, an 0rtical System arranged to eliminateParallax for red" the amount of .relative movef ment beweer; saidmagnets in a horizontal rl fw, and means for adjusting; an @lement etsaid'optical system simultaneously with the adj ist-ment of saidmagnets.

2. il compass-varirometer comprising two di'etfiarsrlee magnet-SSurreled 01.1@ above the other and mounted liorjfree inde-v pendent'`rotationf in. ak horizontel*planay means for limiting the amount ofsaidroion, means :for inovinmfrr said inagnetstoi k n ,l m each other,and; means ,et-ermining the movement of said magnets in said hormonalPlane! f 3. A compass variometer comprising two direction-seekingmagnets supported one above the other and mounted for free inde-ypendent iotation .in a hoi" onta-l planepmeans for limiting the amountojl such rotationyand -ns for reading` the amountot rotation.

. A compass variometer comprising two magnets supported one above theother 'for f free independent rotation in 'a horizontal. plane.,` meansfor limiting` the amount ot such rotation, and means including anoptical system for reading the amount of rotation and 'for eliminatingparallax.

5. -A compass-variometer for direct read-` ings with a selecteddeflection angle, com prismg two magnets supported one above another andhaving their magnetic axes arranged at a selected angle, means forvarying at will the vertical distance between said magnets to maintainsaid angle constant for different intensities of magnetic field, saidmeans having a scale indicating; directly the intensity of the magneticfield.

6. A compass-variometer for direct readinfnr with a selected deflectionangle7 com-V prising' two disk magnets ot equal magnetic momentsupported one above another and having` their magnetic axes arranged ata selected angle in a magnetic field, d means for moving said magnetssimultaneously toward and from each other to maintain said selectedangle in a field of dillerent intensity, and means cooperating` withsaid moving means for indicating,` the intensity of the magnetic field.

7. A compass-variometer comprising two disk magnets supported one yaboveanother in separate containers, liquid damping' means in each containerand means lor varyinny at will the distance between said magy.

nets.

8. A compass-variometer comprising two dish magnets supported one aboveanother with their pivots in vertical alignment, said magnets havingtheir axes arranged asef .lected horizont-al deflection angle, anoptical system arranged to eliminate parallax for reading the amount ofrelative angular movement between the axes ot said 'magu, WW.. W

nets in a horizontal plano, an element oi said system being locatedmid-Way between said magnets and means for Varying at will, equallyand.simultaneously the distance between said magnets and said element.

9. A compass-Variometer comprising` two magnets pivotally supported oneabove another with their pivots in vertical alignment and tree to rotatein a horizontal plane, said magnets having their magnetic axes arrangedat a selected angle, a pointer carried by one magnet and indicating` itsmagnetic axis, a pointer carried by the other magnet and arranged at theselected angle with respect to its magnetic axis, so that the pointerswhen viewed from above appear in vertical alignment, and scale means bymeans of which the angular relation of the pointers may be observed Whenthe intensity of the magnetic iield is increased or decreased, saidscale means reading directly in terms of the intensity ot the magneticiield.

l0. ,A compass-variometcr for direct readings with a selected deflectionangle, comprising two magnets supported one above another on the sameVertical axis for t'ree horizontal rotation, means for indicating theangular relation ot the magnetic axes oi' said magnets and arranged at aselec-ted angle with respect to each other, an optical system forobserving the angular relation ot said means, an element ol said systembeing located mid-Way between said magnets, and means for varying atWill, equally and simultaneously the distance between each magnet andsaid element to maintain said selected angle, said last named meanshaving indicating means indicating` directly the intensity of themagnetic field.

In testimony whereof, We have hereunto subscribed our names.

' LOUIS A. BAUER.

VvlILLli-thl J. PETERS, JOHN A. FLEMING.

n O C

